This study will apply statistical pattern recognition techniques to gait analysis data in a large group of ambulatory patients with spastic diplegia. Boston Children's Hospital, San Diego Children's Hospital and Newington Children's Hospital, all University-affiliated teaching centers with compatible gait analysis facilities will embark jointly to gather gait analysis data on ambulatory patients with spastic diplegia. Gait parameters measured will include rotations of the lower extremity joints in the sagittal, frontal, and transverse planes; overall performance parameters (vel., cadence, etc.); electromyograms, and force plate measurements. It is anticipated that 340 subjects will be examined twice during the course of this study. The data from these gait analyses will be subjected to an interactive process of clustering and feature selection which will conclude with the definition of classes of subjects. This study is unique in that it combines the talents of three university affiliated teaching hospitals. Once homogeneous patterns of involvement in spastic diplegia have been determined, treatment protocols currently being used can be more objectively evaluated. As a result, appropriate treatment regimens could be developed and ineffective or deleterious treatment eliminated. This would reduce morbidity and health care costs for patients with spastic diplegia.